Three tier server



FIG. 1 is a perspective view of a three tier server showing our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a side elevational view thereof;

FIG. 4 is a top plan view thereof; and,

FIG. 5 is a bottom plan view thereof.

The dotted-line showing in the drawings illustrates environmental matter and forms no part of the claimed design. 

CLAIM The ornamental design for a three tier server, as shown and described. 